微信公众号支付，JSAPI支付方法，ThinkPHP5+微信支付

<?php

namespace app\index\controller;

use app\common\controller\HomeBase;
use tools\WxPay;
use think\Config;
use phpqrcode\ApiQrcode;
use think\Request;
use think\Cache;
use tools\RetJosn;

/**
 * JSAPI支付DEMO
 * Class Index
 * @package app\index\controller
 */
class Jsapi extends HomeBase {

    /**
     * 首页
     */
    public function index() {
        $redirect_uri = urlencode('http://wxpay.ngrok2.xiaomiqiu.cn'.url('Jsapi/index2'));
        $url = 'https://open.weixin.qq.com/connect/oauth2/authorize?appid='.Config::get('wx_pay')['appid'].'&redirect_uri='.$redirect_uri.'&response_type=code&scope=snsapi_base&state=123#wechat_redirect';
        $this->redirect($url);
    }


    /**
     * 授权后跳转到此
     */
    public function index2(Request $request){
        $arr = $request->get();
        $code = $arr['code'];
        $url = 'https://api.weixin.qq.com/sns/oauth2/access_token?appid='.Config::get('wx_pay')['appid'].'&secret='.Config::get('wx_pay')['secret'].'&code='.$code.'&grant_type=authorization_code';
        $ret_json = file_get_contents("$url");
        $ret_arr = json_decode($ret_json,true);
        $openid = $ret_arr['openid'];
        $this->assign('openid',$openid);
        return $this->fetch();
    }


    /**
     * 下单获取支付参数
     * @param Request $request
     * @param WxPay $wxpay
     * @return \think\response\Json
     */
    public function getUrl(Request $request,WxPay $wxpay) {
        $pid = $request->get('id');
        $openid = $request->get('openid');
        //调用统一下单API
        $params = [
            'appid' => Config::get('wx_pay')['appid'],
            'mch_id' => Config::get('wx_pay')['mchid'],
            'nonce_str' => md5(time()),
            'body' => '订单号：'.$pid,
            'out_trade_no' => $pid,
            'total_fee' => 2,
            'spbill_create_ip' => $_SERVER['SERVER_ADDR'],
            'notify_url' => Config::get('wx_pay')['notify'],
            'trade_type' => 'JSAPI',
            'product_id' => $pid,
            'openid' => $openid
        ];
        $arr = $wxpay->unifiedorder($params);
        $wxpay->logs('logs.txt',$arr);

        if (isset($arr['prepay_id'])) {
            //重新签名
            $data = [
                'appId' => $arr['appid'],
                'timeStamp' => time(),
                'nonceStr' => md5(time()),
                'package' => 'prepay_id='.$arr['prepay_id'],
                'signType' => 'MD5'
            ];
            $data = $wxpay->setSign($data);
            $data['paySign'] = $data['sign'];
            unset($data['sign']);
            Cache::set('send' . $params['out_trade_no'], $params['total_fee'], 3600);
            return RetJosn::successJson('OK',$data);
        } else {
            return RetJosn::errorJson('err');
        }
    }

    /**
     * 接收腾讯推送支付通知
     * @param WxPay $wxpay
     */
    public function backOrder(WxPay $wxpay) {
        try {
            // 获取腾讯传回来的通知数据
            $xml = $wxpay->getPost();
            // 将XML格式的数据转换为数组
            $arr = $wxpay->XmlToArr($xml);
            $wxpay->logs('logs.txt', '1');
            // 验证签名
            if ($wxpay->checkSign($arr)) {
                Cache::set('back'.$arr['out_trade_no'],$arr['total_fee'],3600);
            }
            $wxpay->logs('logs.txt', '2');
            $params = [
                'return_code' => 'SUCCESS',
                'return_msg' => 'OK'
            ];
            echo $wxpay->ArrToXml($params);
        } catch (\Exception $e) {
            $wxpay->logs('logs.txt', $e->getMessage());
            exit();
        }
    }

    /**
     * 查询支付状态
     * @param Request $request
     * @return type
     */
    public function checkSuccess(Request $request)
{
        $pid = $request->get('id');
        if (Cache::get('send' . $pid) == Cache::get('back' . $pid)) {
            return RetJosn::successJson('支付成功');
        } else {
            return RetJosn::errorJson(Cache::get('send' . $pid) . '|' . Cache::get('back' . $pid));
        }
    }
}


微信支付类：
<?php

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */

namespace tools;
use think\Config;
/**
 * Description of WxPay
 *
 * @author admin
 */
class WxPay {

    /**
     * 获取签名
     * @param type $arr
     * @return type
     */
    public function getSign($arr)
{
        //去除数组的空值
        array_filter($arr);
        if(isset($arr['sign'])){
            unset($arr['sign']);
        }
        //排序
        ksort($arr);
        //组装字符
        $str = $this->arrToUrl($arr) . '&key=' . Config::get('wx_pay')['key'];
        //使用md5 加密 转换成大写
       return strtoupper(md5($str));
    }

    /**
     * 校验签名
     * @param type $arr
     * @return boolean
     */
    public function checkSign($arr){
        //生成新签名
        $sign = $this->getSign($arr);
        //和数组中原始签名比较
        if($sign == $arr['sign']){
            return true;
        }else{
            return false;
        }
    }

    /**
     * 获取带签名的数组
     * @param array $arr
     * @return type
     */
    public function setSign($arr)
{
        $arr['sign'] = $this->getSign($arr);
        return $arr;
    }

    /**
     * 数组转URL字符串 不带key
     * @param type $arr
     * @return type
     */
    public function arrToUrl($arr)
{
        return urldecode(http_build_query($arr));
    }

    /**
     * 记录到文件
     * @param type $file
     * @param type $data
     */
    public function logs($file,$data)
{
        $data = is_array($data) ? print_r($data,true) : $data;
        file_put_contents('./public/paylogs/' .$file, $data);
    }
    /**
     * 接收POST推送
     * @return type
     */
    public function getPost()
{
        return file_get_contents('php://input');
    }

    /**
     * Xml 文件转数组
     * @param type $xml
     * @return string
     */
    public function XmlToArr($xml)
{
        if($xml == '') return '';
        libxml_disable_entity_loader(true);
        $arr = json_decode(json_encode(simplexml_load_string($xml, 'SimpleXMLElement', LIBXML_NOCDATA)), true);
        return $arr;
    }

    /**
     * 数组转XML
     * @param type $arr
     * @return string
     */
    public function ArrToXml($arr)
{
        if(!is_array($arr) || count($arr) == 0) return '';

        $xml = "<xml>";
        foreach ($arr as $key=>$val)
        {
                if (is_numeric($val)){
                        $xml.="<".$key.">".$val."</".$key.">";
                }else{
                        $xml.="<".$key."><![CDATA[".$val."]]></".$key.">";
                }
        }
        $xml.="</xml>";
        return $xml;
    }

    /**
     * 发送POST请求
     * @param type $url
     * @param type $postfields
     * @return type
     */
    public function postStr($url,$postfields)
{
        $ch = curl_init();
        $params[CURLOPT_URL] = $url;    //请求url地址
        $params[CURLOPT_HEADER] = false; //是否返回响应头信息
        $params[CURLOPT_RETURNTRANSFER] = true; //是否将结果返回
        $params[CURLOPT_FOLLOWLOCATION] = true; //是否重定向
        $params[CURLOPT_POST] = true;
        $params[CURLOPT_SSL_VERIFYPEER] = false;//禁用证书校验
        $params[CURLOPT_SSL_VERIFYHOST] = false;
        $params[CURLOPT_POSTFIELDS] = $postfields;
        curl_setopt_array($ch, $params); //传入curl参数
        $content = curl_exec($ch); //执行
        curl_close($ch); //关闭连接
        return $content;
    }

    /**
     * 统一下单
     * @param type $params
     * @return boolean
     */
    public function unifiedorder($params)
{
        //获取到带签名的数组
        $params = $this->setSign($params);
        //数组转xml
        $xml = $this->ArrToXml($params);
        //发送数据到统一下单API地址
        $data = $this->postStr(Config::get('wx_pay')['uourl'], $xml);
        $arr = $this->XmlToArr($data);
        if($arr['result_code'] == 'SUCCESS' && $arr['return_code'] == 'SUCCESS'){
            return $arr;
        }else{
            $this->logs('error.txt', $data);
            return false;
        }
    }
}


前端页面：
<!DOCTYPE html>
<!--
To change this license header, choose License Headers in Project Properties.
To change this template file, choose Tools | Templates
and open the template in the editor.
-->
<html>
    <head>
        <title>TODO supply a title</title>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1" />
    </head>
    <body>
        <h1 id="openid"></h1>
        <div class="btn-box">
            <button onclick="getUrl()">下单</button>
        </div>
        <div id="info">

        </div>
    </body>
    <script src="__STATIC__/default/js/jquery-1.9.1.min.js"></script>
    <script>
        var openid = '';
        $(function () {
            localStorage.getItem('openid');
            if (localStorage.getItem('openid')) {
                openid = localStorage.getItem('openid');
            } else {
                openid = '{$openid}';
                localStorage.setItem('opendi',openid);
            }
            $('#openid').html(openid);
        });

        /*验证码生成*/
        function getUrl() {
            var id = getId(10);
            $.ajax({
                url:"{:url('Jsapi/getUrl')}?id=" + id + '&openid=' + openid,
                dataType:'json',
                success:function(res) {
                    if (res.code == 200) {
                        alert('1'+JSON.stringify(res));
                        var data = res.data;
                        wakeup(res.data);
                        checkSuccess(id);
                    }
                }
            });
        }

        function wakeup(data){
            WeixinJSBridge.invoke(
                'getBrandWCPayRequest', data,
                function(res){
                    if(res.err_msg == "get_brand_wcpay_request:ok" ){
                        // 使用以上方式判断前端返回,微信团队郑重提示：
                        //res.err_msg将在用户支付成功后返回ok，但并不保证它绝对可靠。
                        alert('支付成功');
                    }
                });
        }


        /*生成唯一Id*/
        function getId(length){
            var tmp = Date.parse( new Date() ).toString();
            tmp = tmp.substr(0,length);
            return tmp;
        }

        /*轮询支付状态*/
        function checkSuccess(id){
            var interval = window.setInterval(function(){
                $.ajax({
                   url:"{:url('Jsapi/checkSuccess')}?id=" + id,
                   dataType:'json',
                   success:function(res) {
                       if (res.code == 200) {
                           $('#info').html('订单号：'+id+','+res.msg);
                           clearInterval(interval);
                       }
                   }
                })
            },2000)
        }
    </script>
</html>